Percussion cap



Feb. 16, 1965 H. GAWLICK ETAL 3,169,483

PERCUSSION CAP Filed July 1o, 1961 s INV ENTORS HEINZ GA WL /C K HELMUTBENDLER BMW blug-gaga) n@ ATTORN YS 3,169,483 PERCUSSION CAP HeinzGawlick and Helmut Beudler, both of Furth,

Bavaria, Germany, assignors to Dynamit NobelAktiengesellschaft,Troisdorf, Bezirk Cologne, Germany, a German corporation Filed July 10,1961, Ser. No. 123,400

Claims priority, application Germany, July 14, 1960,

8 Claims. (Cl. IGZ-86.5)

The present invention relates to percussion caps, and more particularlyto percussion caps for use in percussion priming or ignition of a majorcharge wherein the body member of the cap has a recess dened thereincontaining a shoulder portion serving as anvil.

Percussion caps for rifle cartridges and revolver cartridges arenormally produced with an impact-sensitive detonator material which isignited by impact upon an anvil within the cartridge. The impact usuallytakes place at the bottom of the percussion cap which causes theignition of the detonator material due to the oppositely positionedabutment, i.e. an ambos or anvil, which is positioned within thepercussion cap itself or is firmly connected with the cartridge shellor` sleeve wall.

Such impact percussion caps may also be used for other purposes than inthe ignition of cartridges. For example, impact percussion caps may beemployed for the ignition of fuses in hand grenades or in artilleryprojectiles, shells, andthe like. Furthermore, impact percussion capsmay serve to ignite a detonator material in the primary fuse of agrenade. Heretofore, however, in the impact percussion caps of thesedevices referred to immediately hereinabove, anvil percussion capsnormally could only be used in practice.

Inasmuch as percussion caps with anvils are compara- -tively expensiveand require particular care in their production, the cost of theforegoing enumerated devices is relatively high.

Furthermore, the impact energy existing in said foregoing devices, suchas grenade fuses or hand grenade fuses is essentially less than in anormal weapon cartridge or the like. The sensitivity of ananvil-percussion cap, however, is limited directly in terms of thebottom strength or thickness of the bottom wall of the percussion cap.In many cases, the conventional construction of percussion caps of thistype is not sucient to assure an unobjectionable ignition for the deviceto be exploded.

It is an object of the present invention to overcome the foregoingdisadvantages and to provide a percussion cap which comprises a bodymember having a recess de- `ned therein which contains a shoulderportion serving as anvil, whereby extremely good sensitivity of ignitionupon impact by a firing pin or the like is assured.

Other and further objects of the invention will become apparent from astudy of the within specification and accompanying drawings, in whichFIG. l illustrates a longitudinal sectional view of a percusssion capconstruction in accordance with the invention,

FIG. 2 illustrates a similar view of an alternate embodiment of theinvention wherein the wall portion remote from the impact end of the capis closed, and

FIG. 3 is a longitudinal sectional View of the percussion cap of FIG. lshown disposed in position in the sleeve of a primer device.

It has been found, in accordance with the present invention that a verysensitive percussion cap may be provided which comprises a body memberhaving a recess defined therein which is partially delined intermediateits depth by a shoulder portion provided in the adjacent body memberinterior surface surrounding the recess. A plate States Patent O "a lgPatented Feb. 16, 1965 ICC means is longitudinally slidably disposedwithin the recess above and in slightly spaced relation to the shoulderportion, the plate means extending across the recess into coveringcontact with the adjacent body member interior surface surrounding therecess. A suitable detonator means or explosive charge occupies the partof the recess below the plate means, including that part of the recesslocated between the plate means and the shoulder portion, slightlyspaced therefrom. In accordance with one embodiment of the invention,the part of the recess below the plate means is in open communicationwith the exterior of the body member by means dening an opening in thebody member remote from the plate means.

In accordance with another embodiment of the invention, the part of therecess below the plate means is closed oit.

The percussion cap may be said to contemplate a construction, includinga tubular metal body having an internal transmission shoulder portiondefined in the internal wall therewithin, a plate means extendingtransversely across the internal opening of the tubular body andabuttingly engaging the surrounding interior wall of such body.Significantly, the plate means is spaced axially a slight distance withrespect to the shoulder portion and detonator material occupies theinterior space of the tubular body between the plate means and theshoulder portion. While both ends of the tubular metal body may be open,in accordance with one embodiment as aforesaid, on the other hand, inaccordance with another embodiment of the invention, only the end of thetubular metal body adjacent the plate means is open whereas the end ofthe tubular body adjacent the detonator means is closed so as to retainthe detonator means in sealed condition between the closed end and theplate means. i

lt will be appreciated, therefore, that the body means may have acentral tubular chamber having one axial portion of smaller crosssection in off-set or partial registry with the other axial portion oflarger cross section, such that the axial point of registry andtransition from the portion of smaller cross section to the portion oflarger cross section deiines a shoulder transverse the axis of thechamber. Accordingly, a foil is sealingly disposed in contact with thewall of the chamber transverse the portion of larger cross section at anaxial point spaced slightly from the shoulder. Therefore, the portion ofsmaller cross section and that part of the portion of larger crosssection in the slight space between the foil and shoulder adequately andconveniently define a receptacle space for detonator material.

Advantageously, in accordance with the invention, an impact percussioncap is provided which may conveniently consist of only one metal elementwhich simultaneously receives the detonator material and serves .asanvil therefor as well. The foil extending across the recess in thesingle metal element seals the detonator material therewithin at thatparticular side of the cap and serves as impact transmitting member forsqueezing the detonator material against the shoulder within the cap to`cause ignition. The single percussion cap metal element thereby avoidsthe need for a separate anvil member and the concomitant expense andproduction di'iculties occasioned thereby.

Referring to the drawings, FIG. 1 illustrates a perforated percussioncap 1 which takes the form of a tubular metal member having an insidewall surface 2 of larger cross section generally defining a top recess4space 3 and an inside wall surface 4 generally defining a bottom recess5. The point of registry or transition from the top recess 3 and thebottom recess 5 denes a shoulder surface 6 transverse to the axis of capl extending from the larger cross sectional diameter indicated at 7 tothe smaller cross sectional diameter indicated at 8. A suitabledetonator material or explosive charge 9, such as for example, mercuryfulminate, is disposed within the bottom recess 5 as well as a slightportion of the top recess 3 above the shoulder surface 6. A foil orplate member is longitudinally slidably disposed across the extent ofrecess 3 in abutting engagement with the inside wall surface 2 of largercross section. The explosive charge 9 completely occupies the spacebetween foil 10 and shoulder surface 6 and is in peripheral engagementwith the adjce'nt wll surface 2 of the top recess 3. Thus a verysensitiverrirn firing' percussion cap is provided which may be fired byslight impact with the tiring tool acting in the direction of the foil10 and in turn the shoulder `surface 6. Foil 10 may be lacquered orcoated with other protective material to prevent moisture from enteringthe cap and the detonator material.

On the other hand, a -bottom recess 11 is provided for openlycommunicating the detonator material 9 with the: bottom end of cap 1. l

This feature may be more clearly appreciated from a study of FIG. 3which shows the cap 1 in accordance with the embodiment of FIG. 1situated within a primer device in sealed condition whereby no moisturemay enter the detonator material 9 by way of opening 11. In thisinstance, cap 1 is placed in a suitable large recess 12 defined in theupper end of sleeve 13 of the primer fuse housing. By means ofoverturned lip 14 at the upper end of sleeve 13, cap 1 is snuglyretained within large recess 12. Primer or delay material 15 is suitablydisposed within central bore 16 in communication with detonator material9 of'cap 1 by reason of opening 11. Both materials 9 and 15, however,are sealed against moisture by reason of the particular constructioninvolved. vOf course, the strueture and function of the primer deviceshown in FIG. 3 is conventional, whereby upo'n impact of percussion cap1, by suitable means, such as a firing pin, ignition will proceed to andthrough the primer material 15 whereby the transmission detonator caplocated in bottom recess 17 will serve to explode the device inconnection with which the arrangement of FIG. 3 is used, in the desiredmanner.

FIG. 2 is similar in construction to FIG. 1, percussion cap 1 in thisinstance having the same elements as those described with respect toFIG. l except that bot- Vtom recess 5 is closed off from the exterior ofcap 1 by Ibottom wall portion 11a in place of the bottom opening 11employed in the embodiment of FIG.V 1. In the construction according toFIG. 2, therefore, the detonator material 9 will be effectively sealedoif from moisture by bottom wall 11a as well as foil 10.

It will be appreciated that in the foregoing constructions, shouldersurface 6 functions as'the anvil of the percussion'cap whereby uponimpact of foil 10, theA detonator material 9 will be placed underpressure sutiicient to cause the ignition thereof.

In accordance with the invention, the bottom recess 5 may be providedwith any desired diameter, although preferably it should beapproximately 0.6 mm. smaller than the inside diameter of the top recess3. The amount of detonator material 9 disposed within the recess portionbelow the foil 10 may be adjusted in accordance with the intended use ofthe percussion cap in each case, but, of course, a certain amount ofsuch material must be present between the anvil surface 6 and the foil10.

' Depending upon the amount of detonator material 9 employed, thediameter of the bottom recess 5 may be varied as well as the thicknessof bottom wall 11a inthe ycase of the embodiment of FIG. 2.

Preferably, the diameter of bottom recess 5 will be 4about 2% of thediameter of top recess 3. The particular quantity of detonator material9 placed above the anvil surface 6 will depend upon the desiredVsensitivity since the tiring pin or other impact means will strike foil10 .andthereby actupon the detonator material 9 immediately therebelow.By varying the strength or thickness ot' foil 10, the direction of theignition flame may be suitably regulated. In this connection, dependingupon the use of the percussion cap, if the ignition iiame is to emergeupwardly toward the end of cap 1 adjacenttthe firing pin, i.e. throughrecess 3, the bottom end of the percussion capsule will be closed ott bywall 11a in the manner shown in FIG. 2.

On the other hand, where the ignition ame is to emerge toward the bottomend of the cap, opening 11 is provided in recess 5 as is the case withthe operation of the device of FIG. 3.

' What is claimed is:

l. Rim ,ignitable percussion cap which comprises a body member having arecess defined therein providing said body member with an interiorsurface, said recess being partially defined intermediate its depth by ashoulder portion provided in the adjacent portion of the interiorsurface of said body member surrounding the recess, a separate thin foillongitudinally slidably disposed within the recess above'and in slightlyspaced relation to the shoulder portion throughouttheir common extent,said thin foil extending across the recess into covering contact withsaid adjacent portion of the interior surface of said body membersurrounding the recess, and an explosive charge occupying the partV ofsaid recess below said thin foil including completely that part of saidrecess located v between the thin foil and the shoulder portion slightlyspaced therefrom and in peripheral engagement with said interiorysurface of said body member.

2. Percussion cap Iaccording -to claim l, wherein the part 1 of saidrecess below said thin foil is in open communication withk the exteriorof the body member by means deining an opening in the body member remotefrom said Y `thin foil being spaced axially a slight dist-ance withrespect tosad shoulder port-ion, and an explosive charge completelyoccupying the'inter-ior space of said tubular body between said thinfoil and said shoulder portion and in peripheral engagement with saidinternal wall of said tubular metal body.

4. Percussion cap according to claim 3, wherein both ends of saidtubular metal body are open.

5. Percussion cap according to claim 3, wherein the endl of said tubularmetal body adjacent said thin foil is open and the end of said tubularmetal body adjacent said explosive charge is closed whereby to retainsaid explosive charge in sealed condition between the closed end and thethin foil.Y o

6.*Percussion cap for rim tiring using slight impact energy whichcomprises a tubular body member having a central chamber longitudinallytherewithin, said chamber yhaving one axial portion of smallercross-section in partial registry with the other axial portion of largercross-section, the axial point of registry and transition from theportion of smaller cross-section to the portion of larger crosssectiondefining ya shoulder transverse to the axis of said chamber, rand animperforate separate at thin foil sealingly disposed within and inlongitudinally slidable contact with the wall of said chamber transverseto the portion of larger cross-section at an Vaxial point spacedslightly from said shoulder, the portion of Vsmaller cross-section andthat part of the portion of larger cross-section in the slight spacebetween said foil and shoulder deiining a receptacle space containing`an explosive charge therewithin cornpletely occupying at least thespace between the foil and shoulder in peripheral engagement with thewall of the chamber Iportion having the larger cross-section, said cap 5being adapted to be fired by slight impact with a firing tool 'acting inthe direction of said foil and in turn said shoulder.

7. Percussion cap according to claim 6, wherein the end of said chamberportion of smaller cross-section remote from said foil is closed fromcommunication with the exterior of the Ibody member While the end ofsaid chamber portion of larger cross-section remote from said shoulderis in open communication with the exterior of the body member by meansdefining an opening in the body member.

8. Percussion cap yaccording to claim 6, wherein both ends of saidchamber are in open communication with the exterior yof the body memberby opening means defined therein.

References Cited in the le of this patent UNITED STATES PATENTSPertuiset et al. May 26, 1868 Hotchkiss May 15, 1877 Parker Feb. 20,1900 Graeme et al Sept. 25, 1906 Landen Dec. 26, 1944 Amthor Mar. 19,1946 Burdett et al Aug. 12, 1947 Morris et al May 11, 1948 Ramsey Ian.13, 1959 FOREIGN PATENTS Italy January, 1933 Sweden Sept. 2, 1947Belgium June 15, 1953

1. RIM IGNITABLE PERCUSSION CAP WHICH COMPRISES A BODY MEMBER HAVING ARECESS DEFINED THEREIN PROVIDING SAID BODY MEMBER WITH AN INTERIORSURFACE, SAID RECESS BEING PARTIALLY DEFINED INTERMEDIATE ITS DEPTH BY ASHOULDER PORTION PROVIDED IN THE ADJACENT PORTION OF THE INTERIORSURFACE OF SAID BODY MEMBER SURROUNDING THE RECESS, A SEPARATE THIN FOILLONGITUDINALLY SLIDABLY DISPOSED WITHIN THE RECESS ABOVE AND IN SLIGHTLYSPACED RELATION TO THE SHOULDER PORTION THROUGHOUT THEIR COMMON EXTENT,SAID THIN FOIL EXTENDING ACROSS THE RECESS INTO COVERING CONTACT WITHSAID ADJACENT PORTION OF THE INTERIOR SURFACE OF SAID BODY MEMBERSURROUNDING THE RECESS, AND AN E XPLOSIVE CHARGE OCCUPYING THE PART OFSAID RECESS BELOW SAID THIN FOIL INCLUDING COMPLETELY THAT PART OF SAIDRECESS LOCATED BETWEEN THE THIN FOIL AND THE SHOULDER PORTION SLIGHTLYSPACED THEREFOM AND IN PERIPHERAL ENGAGEMENT WITH SAID INTERIOR SURFACEOF SAID BODY MEMBER.